Precision Personnel Locator System · Matthew Lowe Electrical and Computer Engineering Worcester...

Precision Personnel Locator System

Matthew LoweElectrical and Computer Engineering

Worcester Polytechnic InstituteWorcester, MA

Inertial Filtering for Improved Position Accuracy in Challenging RF Environments

06/29/2011

JNC 2011

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Overall Project Goal

• Indoor LocalizationTracking

• For first responders• No  Pre‐installed 

Infrastructure• Rapid Deployment

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Inertial RF FusionOverview

• Design an Inertial Tracking solution– Foot Mounted IMU– (Extended) Kalman Filter

• Design an RF algorithm which uses Inertial information at the signal (not range) level– (ISAR) Inverse Synthetic 

Aperture (sART) Singular value Reconciliation Tomography (ISART)

• Close the loop to update the Inertial

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Inertial RF Fusion

IMUData

Fusion Algorithm

RF Data

Inertial System Model

EKF

PhysicalSystem Model

Noise Model

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Physical System Model

• Newtonian Physics • Representing Rotation (Charting)

Charts•Rotation Matrix•Unit Quaternion•Euler Angle

Problems•Closure•Differential Form

ContinuousTime Linearize Discretize

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Inertial RF Fusion

IMUData

Fusion Algorithm

RF Data

Inertial System Model

EKF

PhysicalSystem Model

Noise Model

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Noise Model(Noise Processes)

WGN

Flicker

Bias Walk

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Inertial RF Fusion

IMUData

Fusion Algorithm

RF Data

Inertial System Model

EKF

PhysicalSystem Model

Noise Model

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EKF

Physical SystemModel

IMU Noise Specifications

(From Spec Sheet)

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German Aerospace CenterPublic Data set

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Inertial RF Fusion

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IMUData

Fusion Algorithm

RF Data

Inertial System Model

EKF

PhysicalSystem Model

Noise Model

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sART

• Combines the data at the signal level

• Each point is rephasedas if the signal originated there

• Metric is computed using Singular Value Decomposition

• Each point is compared via its metric value

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Religious Center

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ISART

• Use the benefits of both systems• Inertial is good in the 

short term• RF has no drift

• Use the inertial track to tie together multiple RF measurements

o8

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Slide 14

o8 This looks like your notes, not a slide for the audience.orr, 6/22/2011

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ISART SimulationsART ISART

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ISART Real Data

Inertial  TrackISART  Track

sART Track

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Conclusions

• Designed an Inertial Tracking solution– Contributed a filter creation method which was automated and based on sensor specifications

– Demonstrated validity on a publically available data set

• Design an RF algorithm which uses Inertial information– Contributed an algorithm which mitigates difficult RF environments by using inertial tracks

– Demonstrated preliminary results

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Acknowledgments

• DHS S&T• Analog Devices• Team members (Andrew and Jamie)• German Aerospace Center DLR

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PPL Workshop at WPI sponsored by DHS

• In August WPI will be hosting the 6th annual indoor location workshop

• http://www.wpi.edu/academics/ece/ppl/2011workshop.html or Google “ppl workshop”

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Questions?

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